Gradient syncFURNACE mOD-200

Questions and Answers

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Nicholas MorrisAug 12, 2025
What to do if the Gradient syncFURNACE mOD-200 flame fails during burner operation?
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  Jacob LucasAug 12, 2025
  If your Gradient Water Heater experiences flame failure during burner operation, verify the gas shut-off valve is open and the gas line is at the correct pressure. Also, ensure the gas valve test ports are closed and the differential pressure tube is properly connected. Check for a blocked chimney system and confirm the gas valve is correctly wired, receiving a signal from the ignition module. Inspect the wire harness continuity and check for combustion blower failure. The gas valve air/fuel mixture may need adjustment. Verify the chimney system lengths and vent termination locations, and check for trap pressure switch failure. Finally, verify the function of the ignition module and flame sensor/spark ignitor.
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veronicawardAug 19, 2025
What to do if no flow is detected in Gradient syncFURNACE mOD-200 Water Heater after demand is turned on?
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  Paul MullinsAug 19, 2025
  If your Gradient Water Heater shows no flow detected after demand is turned on, verify the pump is turning on and functioning properly. Ensure the system is pressurized and full of water, and that all air is purged from the system. Check piping valves to ensure they are all open and not blocked. Ensure piping and water is clean and free of dirt and debris and water meets the requirements listing in manual / warranty sheet. Check filters and/or dirt strainers and ensure no blockage; if blockage exists, clean. Check for a faulty flow switch, verifying electrical continuity and proper function of the paddle, and replace if necessary. Ensure wiring is properly terminated between sensor and syncFURNACE OD controller.
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John KingAug 27, 2025
What to do if flame is detected after gas-valve shut-off in Gradient Water Heater?
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  Steven FarrellAug 27, 2025
  If you detect a flame after the gas valve shut-off in your Gradient Water Heater, verify the gas valve is wired correctly and receiving a signal to open from the ignition module, and check the wire harness continuity. If these steps don't resolve the issue, the gas valve has failed and must be replaced immediately.
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donald52Aug 31, 2025
What to do if Gradient syncFURNACE mOD-200 Water Heater fluid pressure is low?
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  Angela HawkinsAug 31, 2025
  If your Gradient Water Heater detects low fluid pressure, check the cold water supply to ensure operation within safe characteristics and pressure limits. Make sure all valves are open, allowing water to enter and fill the system piping. Inspect filters and/or dirt strainers for blockages; clean if necessary. Check for a dirty pressure sensor, ensuring no debris or dirt is on the sensor port; clean gently with a nylon brush or replace if needed. Ensure wiring is properly terminated between the sensor and the syncFURNACE controller.
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Amanda MorenoSep 3, 2025
Why is the Gradient syncFURNACE mOD-200 Water Heater combustion blower RPM unstable?
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  dianabarkerSep 4, 2025
  If your Gradient Water Heater combustion blower RPM is unstable, check for a partially or fully blocked chimney system. Also, check the wiring at the combustion blower, verifying both low voltage control and main power. Identify and replace any failed components, such as wiring, the combustion blower, or the controller.
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Tiffany JacksonSep 7, 2025
How to troubleshoot no RPM from Comb Blwr at startup in Gradient Water Heater?
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  karenbellSep 8, 2025
  If there is no RPM from the combustion blower at startup for your Gradient Water Heater, check for a partially or fully blocked chimney system. Then, check the wiring at the combustion blower, verifying both low voltage control and main power. Identify and replace any failed component, such as the wiring, combustion blower, or controller.
B
brandy50Nov 15, 2025
What to do if Gradient Water Heater burner fails to ignite due to ignition module lockout?
- D
  Dawn HunterNov 15, 2025
  If the Gradient Water Heater burner fails to ignite due to ignition module lockout, first verify the gas shut-off valve is open and the gas line is at the correct pressure. Ensure the gas valve test ports are closed and the differential pressure tube is properly connected. Check for a partially or fully blocked chimney system. Verify the gas valve is wired correctly and receiving a signal to open from the ignition module, and check the wire harness continuity. Check for combustion blower failure. The gas valve air/fuel mixture may require adjustment. Verify chimney system lengths and vent termination locations, and check for direct wind blowing onto the vent termination. Also, check for trap pressure switch failure. Finally, verify the function of the ignition module and flame sensor/spark...
J
jennifer59Nov 23, 2025
What to do if Gradient Water Heater has no power at ignition (Hi-Limit Safety Open)?
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  Kenneth WilliamsNov 23, 2025
  If your Gradient Water Heater has no power at ignition due to a high-limit safety open, identify which high-limit safety has opened and verify wire harness continuity. Note that safeties are connected to HIGH VOLTAGE LINE (115Vac). If the Vent Limit Switch is open, it indicates the heat exchanger temperature is above the switch setpoint; this switch is NOT resettable, and the heat exchanger must be replaced. If the Water Supply Hi-Limit Switch is open, it means the actual supply water temperature is above the switch setpoint; this switch will auto-reset once the temperature drops 10°F below the setpoint. If the Condensate Trap Pressure Switch is open, it suggests an undersized drain or partial/full trap blockage. If all safeties are closed and not receiving power, check the controller to s...

Summary

Guideline to Symbols

General and Safety Instructions

Included in Packaging

Lists the items included in the product packaging for installation and setup.

Regulatory & General Installation Requirements

Product Information & Specifications

Model Number Identification

Explains how to identify the specific model number of the syncFURNACE OD unit.

Components

Illustrates and names the various components of the syncFURNACE OD unit.

Dimensions and Connection Descriptions

Installation

Minimum Clearances

Specifies the required clearances around the unit for safety and service access.

Mechanical Room & Combustion Air Supply Requirements

Details requirements for the installation location and combustion air supply.

General Venting

Acceptable Vent Configurations

Outlines the approved configurations for venting the syncFURNACE OD.

Acceptable Vent Materials Equivalent Lengths

Lists approved vent materials and their equivalent lengths for system design.

Room Dependent Combustion Air Supply

Connecting Vent Pipe to syncFURNACE OD

Venting Termination Options

Venting Termination Clearances

Condensation Trap

Gas Line Connection

Plumbing syncFURNACE OD

Plumbing Setup - Water Heater (Base Version)

Illustrates external piping for the base version water heater setup.

Plumbing Setup - DHW Re-circ Version

Illustrates external piping for the DHW re-circulation version setup.

syncFURNACE OD Fan-coil

Water Supply Quality Requirements

Purging Air from syncFURNACE OD

Connecting Control (Low-Voltage) Wiring

Connecting Main Power (115 VAC) Wiring

Fan-Coil Installation

Return Air Duct Options

Shows different options and requirements for connecting the return air duct to the fan-coil.

Control Setup

Default Settings

Lists the default configuration settings for various system functions like heating and DHW.

Navigating the Controller

Main Information Screens

Describes the various screens displaying system information like temperatures, pressures, and flow rates.

Setup Menu

Zone Setup

Explains how to set up and customize settings for different HVAC zones.

Burner Setup

Used to force burner operation for calibration, analysis, and input rate adjustments.

Setup Menu Commissioning

Used to manually operate components for air removal and system purging before ignition.

Commissioning

Testing Water Pressure

Provides steps to leak test the plumbing system and verify pressure.

Testing No Gas Safety

Describes how to test the safety lockout feature for gas supply failure.

Testing Gas Inlet Pressure

Testing Combustion

Maintenance & Service

Burner Cleaning

Provides step-by-step instructions for annual burner cleaning.

Clean Combustion Chamber

Details the annual procedure for cleaning the combustion chamber.

Check and Clean Condensation Line and Trap

Outlines the semi-annual procedure for checking and cleaning the condensation line and trap.

Flue Gas Vent & Air Intake Sealing

Instructions for annually inspecting and sealing the flue gas and air intake vents.

Igniter & Flame Sensor Electrodes

Details the annual inspection and cleaning of igniter and flame sensor electrodes.

Troubleshooting

Fault Codes and Corrective Actions

Lists potential fault codes, their descriptions, lockout types, and corrective actions.

Internal Wiring Diagram

Sequence of Events

Replacement Parts List

Handling Instructions for Refractory Cement Fibers (RFC)

Annual Inspection & Maintenance Record

Internal Pump Specifications

Heat Exchanger Specification

Fan-Coil Performance

5 L Model Fan-Coil Performance

Details the performance data for the 5L model fan-coil unit.

10 L Model Fan-Coil Performance

Provides performance data for the 10L model fan-coil unit.

14 L Model Fan-Coil Performance

Provides performance data for the 14L model fan-coil unit.

18 L Model Fan-Coil Performance

Provides performance data for the 18L model fan-coil unit.

22 L Model Fan-Coil Performance

Provides performance data for the 22L model fan-coil unit.

Temporary Construction Heat

Example Humidifier Wiring Diagram